From teen victims Libby German and Abby Williams to Alonzo Brooks to the 'Jennings 8' and more, we look at some murder cases that investigators could use the public's help in solving.

Abdon Pallasch, former legal affairs reporter, spoke with A&E True Crime about his years reporting on R. Kelly and why it took nearly three decades for the singer to be prosecuted for his crimes against underage girls.

Shi Yan, an assistant professor at Arizona State University's School of Criminology and Criminal Justice, spoke with A&E True Crime about the importance of plea bargains and their impact on today's criminal justice system.

On January 13, 1992, the serial killer changed his plea from not guilty to guilty but insane, which removed the need for a criminal trial and forced the verdict to be based on the jury's decision of his mental state.

On December 4, 1978, Billy Milligan, who was charged with the kidnapping, robbery and rape of three women, became the first defendant found not guilty by reason of insanity due to multiple personality disorder, now reclassified as dissociative identity disorder.

Robert A. Jensen, former co-owner of a mass fatality response company, speaks with A&E True Crime about the impact of reuniting families with the material accessories of a life cut short.

The Florida man stole from his family and then murdered his parents and brother after they disapproved of his "relationship" with a Bulgarian cam model he had never met in real life

The officer's murder was investigated by the FBI for more than five decades. And while all of the prime suspects were members of the Ku Klux Klan, no one has ever been charged.

On New Year's Eve 2018, U.S. Army Sergeant, Tyrone Hassel III was murdered by his wife, Kemia Hassel, and her lover, Jeremy Cuellar, who were also soldiers.

According to testimony from friends and family, victims of the "Killer Clown" shared some surprising common connections and tragedies in their lives.